The human activity of destroying or causing irreparable damage to entire natural ecosystems over extremely large areas, typically in the interests of economic gain, or occassionally, for military purposes.

Justin: "Whoa! Did you see where Canada is committing total ENVIROCIDE all around Alberta's Athabasca Oilsands?"

Brittany: "Yeah, like, you can see the effects from space, like, on Google Earth. The area's the size of, like, all of Florida!"